1. Field of the Invention
The invention relates to a device for forming a stack of successively arranged printed sheets, comprised of a conveying device supplying the printed sheets in an imbricated arrangement vertically to a stack support and a controllable insertion device correlated with the stack support provided for stack formation and forming the length of the stack by end plates being moved at the stack ends into an intermediate insertion position between the support elements and the stack.
2. Description of the Related Art
Stacks which are formed in this way are referred to in technical jargon as xe2x80x9cbundlesxe2x80x9d and the device for producing such bundles is referred to as a xe2x80x9cbundlerxe2x80x9d. The pressed and tied bundles are conventionally first stored intermediately and are then transported to a feeder that is provided for feeding the printed sheets to a processing line and that separates or individualizes the printed sheets.
A device of the aforementioned kind is disclosed in Swiss patent application 663 397. The end plates, which are inserted by hand primarily as a protection against damage of the printed sheet at the ends, require the presence of an operator 100% of the time; the operator, to a large degree, has to concentrate on a correct insertion of the end plates between the formed stacks and the support elements which support the stack at its ends. Monitoring of the paper flow in the supply area and the pressing process of the stack before delivery is limited to a large degree as a result of the time required for the manual insertion of the end plates; also, the readying of the end plates can hardly be accomplished by a single operator during operation of the device.
It is therefore an object of the present invention to provide an automation of the feeding action of the end plates to the ends of the stacks in order to make the work assignment easier for the operator and to provide sufficient time for monitoring of the collecting process that is under way as well as readying of the end plates.
In accordance with the present invention, this is achieved in that the insertion device is embodied so as to be correlated with the leading and trailing ends of the stack, provided with passages for the support elements which pass therethrough, drivable perpendicularly against the stack support, and configured to insert the end plates at the ends of the stack. This insertion device has at least one interstice that can receive an end plate. With such a device, the aforementioned disadvantages are substantially eliminated.
Preferably, the insertion device has at least two parallel securing plates receiving an end plate in the interstice.
The insertion device can have two interstices correlated with one end plate of a stack, respectively, so that fewer movements of the insertion device are required and more time is available for the insertion of the end plates.
It is advantageous when the insertion device can be loaded with the end plates in a receiving position which is displaced relative to the stack support at a right angle so that the readying of the end plates is simplified.
It appears to be expedient to load the insertion device with end plates in a retracted receiving position relative to the stack support so that an easily accessible storage or supply space is provided.
The adaptation of the end plate movement to the continuous stack formation process can be optimized when the insertion device is movable back and forth in the stack formation direction.
Preferably, the insertion device is arranged above the horizontally oriented stack support so that the end plates as a result of their own weight or by means of a transfer device can drop or can be moved into the insertion position.
Expediently, the securing plates are guided in a stationarily arranged stand parallel to the stack formation direction so that a simple drive can be used for generating the movements.
In order to be able to move the end plates on the shortest possible path into the operative intermediate position between the stack and the support elements, it is beneficial when at least one of the securing plates is provided with a retaining device which can be moved or switched into the interstice and is arranged above the passages, which are provided for the support elements to allow them to pass therethrough.
It has been proven to be expedient when the receiving position provided for loading the end plates is in the form of a magazine for stacking and dispensing end plates.